"""
描述：用Cursor作为客户端，通过MCP协议，访问MCP服务端，调用MCP服务端的两个工具 
get-alerts 和 get-forecast，联网获取天气预警和天气预报
该代码是一个查询天气的MCP服务器端，包含两个工具：get-alerts 和 get-forecast
注：该示例代码采用的 NWS API 只能查询美国的地区天气
参考链接：https://zhuanlan.zhihu.com/p/29638445068
"""

from typing import Any
import httpx
from mcp.server.fastmcp import FastMCP

# Initialize FastMCP server
mcp = FastMCP("weather")
# Constants
NWS_API_BASE = "https://api.weather.gov"
USER_AGENT = "weather-app/1.0"


async def make_nws_request(url: str) -> dict[str, Any] | None:
    """Make a request to the NWS API with proper error handling."""
    headers = {
        "User-Agent": USER_AGENT,
        "Accept": "application/geo+json"
    }
    async with httpx.AsyncClient() as client:
        try:
            response = await client.get(url, headers=headers, timeout=30.0)
            response.raise_for_status()
            return response.json()
        except Exception:
            return None
def format_alert(feature: dict) -> str:
    """Format an alert feature into a readable string."""
    props = feature["properties"]
    return f"""
            Event: {props.get('event', 'Unknown')}
            Area: {props.get('areaDesc', 'Unknown')}
            Severity: {props.get('severity', 'Unknown')}
            Description: {props.get('description', 'No description available')}
            Instructions: {props.get('instruction', 'No specific instructions provided')}
            """

@mcp.tool()
async def get_alerts(state: str) -> str:
    """Get weather alerts for a US state.
    Args:
        state: Two-letter US state code (e.g. CA, NY)
    """
    url = f"{NWS_API_BASE}/alerts/active/area/{state}"
    data = await make_nws_request(url)
    if not data or "features" not in data:
        return "Unable to fetch alerts or no alerts found."
    if not data["features"]:
        return "No active alerts for this state."
    alerts = [format_alert(feature) for feature in data["features"]]
    return "\n---\n".join(alerts)

@mcp.tool()
async def get_forecast(latitude: float, longitude: float) -> str:
    """Get weather forecast for a location.
    Args:
        latitude: Latitude of the location
        longitude: Longitude of the location
    """
    # First get the forecast grid endpoint
    points_url = f"{NWS_API_BASE}/points/{latitude},{longitude}"
    points_data = await make_nws_request(points_url)
    if not points_data:
        return "Unable to fetch forecast data for this location."
    
    # Get the forecast URL from the points response
    forecast_url = points_data["properties"]["forecast"]
    forecast_data = await make_nws_request(forecast_url)
    if not forecast_data:
        return "Unable to fetch detailed forecast."
    
    # Format the periods into a readable forecast
    periods = forecast_data["properties"]["periods"]
    forecasts = []
    for period in periods[:5]:  # Only show next 5 periods
        forecast = f"""
                    {period['name']}:
                    Temperature: {period['temperature']}°{period['temperatureUnit']}
                    Wind: {period['windSpeed']} {period['windDirection']}
                    Forecast: {period['detailedForecast']}
                    """
        forecasts.append(forecast)
    return "\n---\n".join(forecasts)


if __name__ == "__main__":
    # Initialize and run the server
    mcp.run(transport='stdio')